Method for the production of hollow metallic cases



March 19,1940- J. B. TALBOT-CROSBIE ET AL 2,193,891

METHOD FOR THE PRODUCTION OF HOLLOW METALLIC CASES Filed July 1, 1939@7; jmgmnmkammu Patented Mar. 19, 1940 1 METHOD FOR THE. PRODUCTION OFHOLLOW METALLIC CASES John Burrell Talbot-Crosbie and. Arthur PenrhynStanley Macquisten, Glasgow, Scotland Application July 1, 1939, SerialNo. 282,396 In Great Britain July 4, 1938 3 Claims.

This invention relates to an improved method for the production ofhollowmetallic cases and the like, more particularly ammunition shellsor shell cases, produced from a steel billet.

The invention is particularly applicable to the production of ammunitionshell cases by a forging and extrusion process.

porarily closed.

then extruded through the die.

Broadly, the present invention contemplates local cooling of the billetprior to extrusion whereby to reduce or control the ductility orextrusibility of a selected part or parts of the billet, whereby thesurface next to any part of the tools may be rendered less liable toextrude in a direction other than that planned.

In the production of ammunition shell cases by a forging and/orextrusion process such as above referred to there is a liability toformation of a fin between the plunger and the wall of thebillet-receiving chamber, since, in practice, a certain clearance isgenerally allowed between these parts. I

We avoid or reduce the tendency to the formation of such a fin bycooling the billet over an outer annular area on the face of the billetwhich i is subjected to the action of the moving tools,

say the upper face of the billet.

In practice the cooling may be effected immediately prior to the forgingoperation by, for instance, partial immersion of the billet in water,while preferably shielding or screening the central or other parts ofthe submerged face, the billet being inverted before introduction intothe chamber.

One form of apparatus used for effecting the local cooling isillustrated diagrammatically in the figure of the accompanying drawing.

As shown the apparatus comprises a vessel I having a water inletconnection 2 and an overflow 3. On the base of the vessel l is fixed aniron pad 4 concentric with a dished guide plate 5. To cool an outerannular area, of the billet 6, the billet is rested temporarily on thepad 4.

It is to be understood that the local cooling or reduction of temper ofthe billet may be effected in other ways.

What is claimed is:

1. In the production of hollow metallic cases from a steel billet by aforging and extrusion process, the step of cooling the billet locallyprior to extrusion, for the purpose specified.

2. In the production of hollow metallic cases as set forth in claim 1,the step of cooling the billet over an outer annular area on an end faceof the billet,

3. In the production of hollow metallic cases asset forth in claim 1,cooling the billet locally by partial immersion of the billet in waterWhile screening part of the submerged face.

J. B. TALBOT-CROSBIE. A. P. S. MACQUIS'IEN.

